Vorinostat and Capecitabine in Treating Patients With Metastatic or Unresectable Solid Tumors

DISEASE CHARACTERISTICS: * Histologically confirmed malignant solid tumor * Metastatic or unresectable disease * Standard curative or palliative measures do not exist or are no longer effective * Patients who received prior radiotherapy must have measurable disease outside a previously irradiated field OR disease progression after prior radiotherapy * No known brain metastases PATIENT CHARACTERISTICS: Age * 18 and over Performance status * ECOG 0-2 OR * Karnofsky 60-100% Life expectancy * More than 12 weeks Hematopoietic * WBC ≥ 3,000/mm\^3 * Absolute neutrophil count ≥ 1,500/mm\^3 * Platelet count ≥ 100,000/mm\^3 Hepatic * Bilirubin normal * AST and ALT ≤ 2.5 times upper limit normal (ULN) Renal * Creatinine normal OR * Creatinine clearance ≥ 60 mL/min Cardiovascular * No symptomatic congestive heart failure * No unstable angina pectoris * No cardiac arrhythmia Other * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * Able to swallow oral medication * No clinical or radiological diagnosis of bowel obstruction * No ongoing or active infection * No history of allergic reaction attributed to compounds of similar chemical or biological composition to suberoylanilide hydroxamic acid or other agents used in this study * No known dihydropyrimidine dehydrogenase deficiency * No psychiatric illness or social situation that would preclude study compliance * No other uncontrolled illness PRIOR CONCURRENT THERAPY: Biologic therapy * Not specified Chemotherapy * More than 4 weeks since prior chemotherapy (6 weeks for nitrosoureas or mitomycin) and recovered * Prior fluorouracil allowed * No prior capecitabine Endocrine therapy * Not specified Radiotherapy * See Disease Characteristics * More than 4 weeks since prior radiotherapy and recovered * No prior radiotherapy to \> 40% of bone marrow Surgery * At least 4 weeks since prior surgery and recovered Other * At least 2 weeks since prior valproic acid * No other concurrent investigational agents * No other concurrent anticancer therapy * No concurrent combination antiretroviral therapy for HIV-positive patients